Generally they can’t - the pace setters run at a pace above typical max for the distance (but within max for the shorter distance they are running), sheltering the people they’re pacemaking for.
You want to believe things are simple, but they’re not.
Come on. Think things through to the end. If it were actually true that the pace-setters could run faster than the competitors for the full marathon, then the pace-setters would win the event.
What you want to say is that the pace-setters are capable of running a faster pace than the competitors for a shorter distance. Maybe that's true (I doubt it), but it's not responsive. Pace setters are there to set a pace, like a metronome. If the competitors feel this pace is inadequate, there's absolutely nothing stopping them from running faster, or demanding a faster pace-setter.
You didn't, which is exactly the point. It's a critical piece of information for evaluating the truth and relevance of your argument.
I was a distance runner.